Sounding-disk.



C. G. EHRMAN.

SOUNDING DISK.

APPLICATION FILED OUT. 4, 1911.

1,026,256. Patented Ma 14, 1912.

COLUMBIA PLANounAFH 60.. WASHINGTON. o. c.

onrrnn STATES" PATENT ormon CHARLES C. EHRMAN, OF WINTHROP, MASSACHUSETTS, ASSIGNOR T0 EHRMAN MAN- UFACTURING COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MAS- SACHUSETTS.

SOUNDING-DISK.

Specification of Letters Patent.

Patented May 14, 1912.

Application filed October 4, 1911. Serial No. 652,823.

To all whom it may concern Be it known that I, CHARLES C. EI-IRMAN, a citizen of the United States, residing at WVinthrop, in the county of Suffolk and State of Massachusetts, have invented new and useful Improvements in Sounding- Disks, of which the following is a specification.

My invention relates to signaling devices, and its objects are to utilize fully the vibratory qualities of a metal diaphragm in creating sound, to facilitate the manner of production of said vibrations, and to simplify and render more effective the arrangement and operation of the several parts.

My invention primarily consists in firm] y securing against movement in any direction the ends of a curved strip or blade of resilient metal the edges of which are unconfined, a curved back acting as a sounding board being secured directly beneath said strip.

My invention further consists in other novel constructions and modifications more specifically hereinafter pointed out and claimed.

Referring to the drawing, in which similar numerals refer to similar parts, throughout the several views,Figure 1 is a plan view of my improved construction, showing the diaphragm and the spaces on each side of the same. Fig. 2 is a vertical section on line 22 of Fig. 1. Fig. 3 is a section showing a modification of Fig. 2. Fig. 4 is a view in perspective of the diaphragm or blade. the wall of the disk before the diaphragm is secured thereto.

Directing attention to the drawing, the diaphragm 6 is constructed of metal or any other suitable material of a resilient character and is preferably convex in shape. The ends of said diaphragm are cut circular in form in order that the same may engage with the circular holder 7 to which the same is secured. Spaces 8, are left between the edges of said diaphragm and the edges of the holder in order that there may be no obstruction to the movement of the diaphragm when pushed downwardly by the fingers. The holder 7 is preferably constructed of one piece of metal and contains therein the saucer shaped depression 9, the wall of said holder turning back upon itself and forming the convolution 10 for the pur- Fig. 5 is a view showing a section of pose of securing the diaphragm 6. If preferred, the said convolution 10 may be dispensed with and its otlice performed by the ring 11, which operates as a securing device in the same manner as the convolution 10. At the back of said holder, I preferably secure the cover 12 which is here shown composed of a metallic base covered with celluloid, but may, as is obvious, be formed of any si'litable materials. To attach the diaphragm (S, I place the curved ends of the same upon the seat 13 formed at the edge of the holder. The said diaphragm is placed in position while the extreme edge 1 t of the metallic sheet forming the holder is in the position shown in Fig. To secure the diaphragm firmly in positionvit is only necessary to force down upon the same the edge 14, when the ends of the diaphragm will be firmly secured in position. In forming the holder 7, I preferably stamp the same from a single circular sheet of metal and utilize the edge of said sheet as a securing device. It is obvious, however, that a smaller piece of metal could be used, as in Fig. 3, and the office of securing the diaphragm could be satisfactorily performed by a ring such as shown at 11 in Fig. 3.

In the construction of my improved disk, I find that it is necessary in order to secure the best results to ascertain by actual experiment the acoustic properties of the depression 9 as an aid to the development of the sound occasioned by the vibration of the diaphragm 6. The sound arising from said diaphragm as is obvious is produced by depressing with the fingers the central. portion thereof, at which time a sharp click may be heard. Upon releasing the pressure, the diaphragm will return to the position shown in the drawings, when another click will be heard. In order to obtain the best results, I find that it is absolutely essential to rigidly confine the extremities of the diaphragm and also that spaces be left on each side of the diaphragm in order that the sound may be properly produced. If the ends of the said diaphragm are not firmly and rigidly secured and if spaces are not left at the longer edges of the same and a space of certain acoustic properties pro vided, the results of my invention cannot be secured.

I am aware that sounding disks have heretofore been constructed in which one or both ends of the diaphragm are left unsecured, but from actual experiment with such devices I have found that the device soon wears out and that the sound produced is never of the intensity and loudness produced by the operation of my invention.

My invention will be found of great util-' ity in the hands of the public lecturer who frequently has occasion to attract the notice of his assistant by some device of this character. Electrical signal devices have been used for this purpose but the cost of such devices is considerable as compared with the cost of my improved disk. Electricity is not always available to a lecturer and there is need on the market of a reliable signaling device of the character of my in vention. Then again, my invention will be found of great utility as a toy for children and also as an advertising device in the same manner as the ordinary advertising button or mirror. I

The gist of my invention resides in my conception that in order to produce the greatest volume of sound from a diaphragm of the character employed by me itis essential that the ends be rigidly secured and that the middle portion of the same be free to vibrate, the spaces on each side of the said diaphragm necessarily contributing to 1 the production of the volume of sound as well as the acoustic properties of the holder.

That I claim and desire to secure by Let ters Patent is,

1. A sounding disk consisting of a holder having a depression therein, a diaphragm, the ends of which are secured to said holder, each side of the diaphragm being separated by a space from the edges of said holder.

2. A sounding disk consisting of a. holder having a depression therein, a convex diaphragm the ends of which are secured to said holder, each side of the diaphragm being separated by a space from the edges of said holder.

3. A sounding disk consisting of a holder with a depression therein formed from one piece of metal, a convex diaphragm the ends of which are secured to said holder, each side of the diaphragm being separated by a space from the edges of said holder.

4:. A sounding disk consisting of a holder having a depression therein, a convex diaphragm the ends of which are immovably secured to said holder, each side of said diaphragm being separated by a space from the edges of said holder.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses, this 2nd day of October 1911.

CHARLES C. EHRMAN.

Witnesses ROBERT JAoKsoN CRANE, MARY A. HEYWOOD.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. 

